Experimental and theoretical studies of rate coefficients for the reaction O(P3)+CH3OH at high temperatures

Rate coefficients of the reaction O(P3)+CH3OH in the temperature range of 835–1777K were determined using a diaphragmless shock tube. O atoms were generated by photolysis of SO2 with a KrF excimer laser at 248nm or an ArF excimer laser at 193nm; their concentrations were monitored via atomic resonance absorption excited by emission from a microwave-discharged mixture of O2 and He. The rate coefficients determined for the temperature range can be represented by the Arrhenius equation, k(T)=(2.29±0.18)×10−10exp[−(4210±100)∕T]cm3molecule−1s−1; unless otherwise noted, all the listed errors represent one standard deviation in fitting. Combination of these and previous data at lower temperature shows a non-Arrhenius behavior described as the three-parameter equation, k(T)=(2.74±0.07)×10−18T2.25±0.13exp[−(1500±90)∕T]cm3molecule−1s−1. Theoretical calculations at the Becke-3-Lee–Yang–Parr (B3LYP)∕6−311+G(3df,2p) level locate three transition states. Based on the energies computed with coupled clusters singles, dou...